as published in the International Primer
The epidemiology of Tuberculosis abroad is well-understood. The high prevalence countries are Mexico, the Philippines, Vietnam, Cambodia, India, China, Haiti, South Korea, and the former Soviet Union. Children living in orphanages abroad are the unwitting victims of this disease. They are exposed to adult caretakers with active tuberculosis who are living and working in the orphanage and have no access to medical care. Caretakers in orphanages are often ill for weeks and months without any medical attention making the spread of TB easy. Orphans have poor nutrition leading to inevitable immunosuppression (decreased ability to fight infection) making them more susceptible to tuberculosis. The incubation period can be weeks, months, and even years. A child arrives in the U.S. well-appearing and can begin to have symptoms over time. The symptoms in a newly adopted children can be very subtle. The child may present to a pediatrician's office with a fever, cough, weight loss, or with a gradual change in mood and loss of developmental milestones. There may be no symptoms at all, in fact, as the disease is just beginning. There may just be a fever and no other symptoms. Unless the doctor is aware of the increased risks of Tuberculosis in orphanages, the diagnosis of TB can be easily missed.
It is recommended that a child who is adopted from abroad be tested with a Mantoux skin test (PPD or purified protein derivative). The skin test is placed on either forearm (under the skin so that there is at least a tiny blister formed initially that resorbs within a few minutes) and should be read by a medical professional between 48 and 72 hours. Multiple puncture skin tests are no longer considered appropriate for TB skin testing. A positive skin test means that the diameter of the raised skin is greater than or equal to 10 mm. In an international adoption clinic at the Floating Hospital in Boston, one hundred and twenty-nine children were medically evaluated between 1989 and 1993. Four (3 percent) children had positive Mantoux skin tests. Two hundred ninety-three children adopted from 15 countries were evaluated between April 1986 and June 1990 at the University of Minnesota adoption clinic and ten (3 percent) children had positive Mantoux skin tests, and four of these had active pulmonary tuberculosis. Two hundred and eighty-six children were tested for TB at the International Adoption Medical Consultation Services in Mineola, New York between 1994 and 1998 and 50 (17.5 percent) children had positive Mantoux skin tests with induration (raised skin) of greater than or equal to 10 mm. All of the children had negative chest films and have had no signs of active disease. The positive skin test tells us that the child has probably been exposed to an adult individual with active Tuberculosis. If the skin test is positive (greater than or equal to 10 mm of induration), then the child should have a chest x-ray performed. If the child's chest x-ray is negative, then the child does not have disease, but rather has been exposed to TB and is not contagious, and will require 9 months of preventive therapy with isoniazid. In a recent e-mail communication from Dr. Nancy Hendrie, a pediatrician who travels abroad and evaluates children for adoption in orphanages in Cambodia, it was revealed that there were three children adopted from Cambodia recently with active Tuberculosis disease.
Children in all countries, except the U.S. and the Netherlands, are given a vaccine (Bacille-Calmette-Guerin or BCG) to prevent tuberculosis. The vaccine has very limited efficacy in the prevention of TB; some physicians are concerned about the interpretation of the PPD skin tests for children with a history of BCG vaccine. The current recommendations for interpretation of the PPD skin test are found in the Redbook 1997 from the American Academy of Pediatrics. It is this author's experience that since internationally adopted children come from countries with a very high prevalence of tuberculosis, the PPD must be regarded as an essential tool for the diagnosis of TB in children. There have been a number of studies designed to assess the effect of BCG vaccine on the PPD test (cross-reaction to BCG) and it is this author's considered opinion that cross-reaction to BCG plays a minimal role in the assessment of TB exposure for children adopted from abroad. A skin test of greater than or equal to 10 mm of induration is positive regardless of BCG status, and is consistent with TB exposure; it warrants a chest film and 9 months of preventive therapy with isoniazid.
For more information about tuberculosis, read International Adoptions Pose Extra TB Risk, Latent Tuberculosis, TB and Other Infectious Diseases, or Tuberculosis in Children Adopted from Abroad in the Medical Resources/Information on Common Diseases/Infectious Diseases and Parasites section of this site.
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American Academy of Pediatrics (1997). Tuberculosis. In G. Peter. (Ed.)1997 Redbook: Report of the Committee on Infectious Diseases. 24th ed. (pp. 541-562). Elk Grove Village, IL: American Academy of Pediatrics.
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January 3, 2000. CXLIX; A1, B5.
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